LaTeX is a high-quality typesetting system; it includes features designed for the production of technical and scientific documentation. LaTeX is the de facto standard for the communication and publication of scientific documents. LaTeX is available as free software.
Most of my short to medium size writing projects are done through Google Doc. I like this web tool because it is simple to use and does not have all that complex and intimidating clutter of authoring tools Word has. Anything you write on a Doc is automatically saved and synced to your Drive account across different devices.
This is the software I use for what I call heavy writing tasks like writing ebooks or chapters for my thesis. Scrivener is not free it costs $45 and there is a discount of 15% for educators and students. There is also a free trial period of 30 days to try it out before you buy it. Scrivener provides access to all the features of a full rich text editor: add tables, bullet points and images and format your text however you want. Here is a list of the features Scrivener provides to its users. If you are a graduate student or a struggling writer, Scrivener is a MUST have. Here is a great read about Scrivener: Thesis Writing with Scrivener.
If you still have that longing to Microsoft Word, try using OpenOffice. This is a free office suite competing with Microsoft Office. It includes word processor, spreadsheet, database, presentations. Compatible with MS Office files.